310 Ordeal of the Ityman Empire in CHAP.

self-preservation drove the province of Gaul and the rich
commercial city of Palmyra in Syria to take the task of
defence into their own hands and organize their territories
as independent kingdoms. In the year 258 Marcus Cassius
Latinius Postumus was ruler of Gaul; at Palmyra, Odenathus
fought in defence of the East against the Persians, and his
example was followed later by his widow, Zenobia.

The more grievous the condition of the empire, the fiercer
grew the pressure of the barbarians upon its frontiers. But
at the same time a feeling gathered strength among the people
that they must, by some means or other, defend the civiliza-
tion of the Roman Empire, save its cities from destruction
and desolation, and restore the unity of the Roman State.
Even the soldiers were stirred by this feeling: they began
to show more stubbornness in the struggle against barbarism,
and more willingness to submit to the discipline enforced
by the emperors whom they themselves had elected. This
imperial temper was exemplified by a succession of strong and
able emperors in the second half of the third century. It is
true that most of them died by violence, and that they were
forced constantly to struggle against mutiny at home ; but
these difficulties did not deter them. If an emperor was
murdered his successor showed, in dealing with the armies, the
same firmness which had cost his predecessor his life at their
hands : he demanded discipline and blind obedience to his
commands in the same uncompromising spirit. The emperors
themselves set an example of self-sacrifice—an example which
was the more effectual, because most of them had begun their
career as common soldiers.

The first of this line of rulers was Claudius, surnamed
Gothicus. He reigned from 268 to 270, and inflicted a decisive
defeat upon the Goths, by which he arrested for a time their
pressure upon the Danube frontier and the Eastern provinces.
His successor, Aurelian, reigned five years. He not only
defended the Danube provinces and Italy against the Germans
but also restored the unity of the empire by means of an army
which he welded into one for a time by a discipline of iron :
in his reign Gaul and Syria again became parts of the state.
His successors—Probus (276-282), Carus, and his son Carinus
—fought with success upon the frontiers. After the death of
Carus, murdered like Probus by his own soldiers, the army
proclaimed Gaius Valerius Aurelius Diocletianus emperor in